But what's the difference?
Self-managed:
The order e-mail goes out to the service provider. I expect the service provider to provide feedback on the order. They confirm the pick-up date of the order and provide feedback on the weight, for example. As the customer, I manage the orders myself.
Managed externally:
No e-mail is sent to the service provider.
As the customer, I do not receive any feedback from the service provider (e.g. no weight). This type of order makes sense for a standard weight or bulk collections.
In this case, the service provider (third party) manages the tours and collections.